Evaluation of 3D cell culture systems for host-pathogen interaction studies

Traditional cell culture models have limitations in extrapolating functional mechanisms that underlie strategies of microbial virulence. Indeed during the infection the pathogens adapt to different tissue-specific environmental factors. The development of in vitro models resembling human tissue physiology might allow the replacement of inaccurate or aberrant animal models. Three-dimensional (3D) cell culture systems are more reliable and more predictive models that can be used for the meaningful dissection of host–pathogen interactions. The lung and gut mucosae often represent the first site of exposure to pathogens and provide a physical barrier against their entry. Within this context, the tracheobronchial and small intestine tract were modelled by tissue engineering approach. The main work was focused on the development and the extensive characterization of a human organotypic airway model, based on a mechanically supported co-culture of normal primary cells. The regained morphological features, the retrieved environmental factors and the presence of specific epithelial subsets resembled the native tissue organization. In addition, the respiratory model enabled the modular insertion of interesting cell types, such as innate immune cells or multipotent stromal cells, showing a functional ability to release pertinent cytokines differentially. Furthermore this model responded imitating known events occurring during the infection by Non-typeable H. influenzae. Epithelial organoid models, mimicking the small intestine tract, were used for a different explorative analysis of tissue-toxicity. Further experiments led to detection of a cell population targeted by C. difficile Toxin A and suggested a role in the impairment of the epithelial homeostasis by the bacterial virulence machinery. The described cell-centered strategy can afford critical insights in the evaluation of the host defence and pathogenic mechanisms. The application of these two models may provide an informing step that more coherently defines relevant molecular interactions happening during the infection.

La ricerca traslazionale in farmacologia gastroenterologica

Il presente studio si concentra sull’analisi degli aspetti traslazionali nella ricerca farmacologica applicata alla Gastroenterologia. La trattazione si articola in due parti: una prima elaborazione teorica, che permette di inquadrare nel contesto della ricerca traslazionale il razionale scientifico ed etico alla base delle attività sperimentali eseguite durante il triennio; una seconda parte, nella quale si riportano i metodi, i risultati e le osservazioni conclusive derivanti dallo studio sperimentale. Nella prima parte vengono analizzate alcune caratteristiche delle procedure, adottate nella ricerca in ambito farmacologico gastrointestinale, che permettono di ottenere un dato verosimile derivabile da modelli diversi rispetto all’organismo umano. Sono inclusi nella trattazione gli aspetti etici dell’utilizzo di alcuni modelli animali di patologie intestinali organiche e funzionali in relazione al loro grado di predittività rispetto alla realtà sperimentale clinica. Nella seconda parte della trattazione, viene presentato uno studio esplorativo tissutale multicentrico sul ruolo del sistema oppioide e cannabinoide nella sindrome dell’intestino irritabile (IBS). Obiettivo dello studio è la valutazione dell’espressione e la localizzazione del recettore oppioide µ (µOR), del suo ligando β endorfina (β-END) e del recettore cannabinoide 2 (CB2) nei pazienti con IBS ad alvo costipato (IBS-C) e diarroico (IBS-D), ed in soggetti sani (HC). I dati ottenuti indicano un’implicazione del sistema oppioide e cannabinoide nella risposta immune alterata riscontrata nei pazienti con IBS ed in particolare nel sottogruppo IBS-C. La presente trattazione suggerisce come la creazione di nuovi sistemi di indagine sempre più validi da un punto di vista traslazionale possa dipendere, almeno in parte, dalla capacità di integrare realtà disciplinari, tecnologie ed esperienze metodologiche diverse nel contesto della ricerca in campo biomedico e farmacologico ed in particolare tramite un mutuo scambio di informazioni tra realtà clinica e ricerca di base

Preparazione di una resina epossidica bio-based e studio delle relative proprietà

Epoxy resins are very diffused materials due to their high added value deriving from high mechanical proprieties and thermal resistance; for this reason they are widely used both as metallic coatings in aerospace and in food packaging. However, their preparation uses dangerous reagents like bisphenol A and epichlorohydrin respectively classified as suspected of causing damage to fertility and to be carcinogen. Therefore, to satisfy the ever-growing attention to environmental problems and human safeness, we are considering alternative “green” processes through the use of reagents obtained as by-products from other processes and mild experimental conditions, and also economically sustainable and attractive for industries. Following previous results, we carried out the reaction leading to the formation of diphenolic acid (DPA), its allylation and the following epoxidation of the double bonds, all in aqueous solvent. In a second step the obtained product were cross-linked at high temperature with and without the use of hardeners. Then, on the obtained resin, some tests were performed like release in aqueous solution, scratch test and DSC analysis.

In Vitro and In Vivo Validation of Human and Goat Chondrocyte Labeling by Green Fluorescent Protein Lentivirus Transduction

We investigated whether human articular chondrocytes can be labeled efficiently and for long-term with a green fluorescent protein (GFP) lentivirus and whether the viral transduction would influence cell proliferation and tissue-forming capacity. The method was then applied to track goat articular chondrocytes after autologous implantation in cartilage defects. Expression of GFP in transduced chondrocytes was detected cytofluorimetrically and immunohistochemically. Chondrogenic capacity of chondrocytes was assessed by Safranin-O staining, immunostaining for type II collagen, and glycosaminoglycan content. Human articular chondrocytes were efficiently transduced with GFP lentivirus (73.4 +/- 0.5% at passage 1) and maintained the expression of GFP up to 22 weeks of in vitro culture after transduction. Upon implantation in nude mice, 12 weeks after transduction, the percentage of labeled cells (73.6 +/- 3.3%) was similar to the initial one. Importantly, viral transduction of chondrocytes did not affect the cell proliferation rate, chondrogenic differentiation, or tissue-forming capacity, either in vitro or in vivo. Goat articular chondrocytes were also efficiently transduced with GFP lentivirus (78.3 +/- 3.2%) and maintained the expression of GFP in the reparative tissue after orthotopic implantation. This study demonstrates the feasibility of efficient and relatively long-term labeling of human chondrocytes for co-culture on integration studies, and indicates the potential of this stable labeling technique for tracking animal chondrocytes for in cartilage repair studies.

In the human urothelium and suburothelium, intradetrusor botulinum neurotoxin type A does not induce apoptosis: preliminary results

Intradetrusor injections of botulinum neurotoxin type A (BoNTA) are emerging as the preferred second-line treatment for neurogenic and idiopathic overactive bladder (OAB). In animal experiments, intradetrusor BoNTA injections have been shown to cause apoptosis in the bladder urothelium and suburothelium but not the detrusor.

Preclinical in vitro and in vivo characterization of the fully human monoclonal IgM antibody KBPA101 specific for Pseudomonas aeruginosa serotype IATS-O11

Pseudomonas aeruginosa infection in ventilator-associated pneumonia is a serious and often life-threatening complication in intensive care unit patients, and new treatment options are needed. We used B-cell-enriched peripheral blood lymphocytes from a volunteer immunized with a P. aeruginosa O-polysaccharide-toxin A conjugate vaccine to generate human hybridoma cell lines producing monoclonal antibodies specific for individual P. aeruginosa lipopolysaccharide serotypes. The fully human monoclonal antibody secreted by one of these lines, KBPA101, is an IgM/kappa antibody that binds P. aeruginosa of International Antigenic Typing System (IATS) serotype O11 with high avidity (5.81 x 10(7) M(-1) +/- 2.8 x 10(7) M(-1)) without cross-reacting with other serotypes. KBPA101 specifically opsonized the P. aeruginosa of IATS O11 serotype and mediated complement-dependent phagocytosis in vitro by the human monocyte-like cell line HL-60 at a very low concentration (half-maximal phagocytosis at 0.16 ng/ml). In vivo evaluation of KBPA101 demonstrated a dose-response relationship for protection against systemic infections in a murine burn wound sepsis model, where 70 to 100% of animals were protected against lethal challenges with P. aeruginosa at doses as low as 5 microg/animal. Furthermore, a high efficacy of KBPA101 in protection from local respiratory infections in an acute lung infection model in mice was demonstrated. Preclinical toxicology evaluation on human tissue, in rabbits, and in mice did not indicate any toxicity of KBPA101. Based on these preclinical findings, the first human clinical trials have been initiated.

Effect of systemic tetracycline on the degradation of tetracycline-impregnated bilayered collagen membranes: an animal study

BACKGROUND: Premature collagen membrane degradation may compromise the outcome of osseous regenerative procedures. Tetracyclines (TTCs) inhibit the catalytic activities of human metalloproteinases. Preprocedural immersion of collagen membranes in TTC and systemic administration of TTC may be possible alternatives to reduce the biodegradation of native collagen membranes. AIM: To evaluate the in vivo degradation of collagen membranes treated by combined TTC immersion and systemic administration. MATERIALS AND METHODS: Seventy-eight bilayered porcine collagen membrane disks were divided into three groups and were immersed in 0, 50, or 100 mg/mL TTC solution. Three disks, one of each of the three groups, were implanted on the calvaria of each of 26 Wistar rats. Thirteen (study group) were administered with systemic TTC (10 mg/kg), while the remaining 13 received saline injections (control group). Calvarial tissues were retrieved after 3 weeks, and histological sections were analyzed by image analysis software. RESULTS: Percentage of remaining collagen area within nonimpregnated membranes was 52.26 ± 20.67% in the study group, and 32.74 ± 13.81% in the control group. Immersion of membranes in 100 mg/mL TTC increased the amount of residual collagen to 63.46 ± 18.19% and 42.82 ± 12.99% (study and control groups, respectively). Immersion in 50 mg/mL TTC yielded maximal residual collagen values: 80.75 ± 14.86% and 59.15 ± 8.01% (study and control groups, respectively). Differences between the TTC concentrations, and between the control and the study groups were statistically significant. CONCLUSIONS: Immersion of collagen membranes in TTC solution prior to their implantation and systemic administration of TTC significantly decreased the membranes' degradation.

Small-animal PET/CT for monitoring the development and response to chemotherapy of thymic lymphoma in Trp53-/- mice

Transgenic mouse models of human cancers represent one of the most promising approaches to elucidate clinically relevant mechanisms of action and provide insights into the treatment efficacy of new antitumor drugs. The use of Trp53 transgenic mice (Trp53 knockout [Trp53(-/-)] mice) for these kinds of studies is, so far, restricted by limitations in detecting developing tumors and the lack of noninvasive tools for monitoring tumor growth, progression, and treatment response.

Preclinical testing of strategies for therapeutic targeting of human T-cell trafficking in vivo

Naive T cells are migratory cells that continuously recirculate between blood and lymphoid tissues. Antigen-specific stimulation of T cells within the lymph nodes reprograms the trafficking properties of T cells by inducing a specific set of adhesion molecules and chemokine receptors on their surface which allow these activated and effector T cells to effectively and specifically home to extralymphoid organs. The observations of organ-specific homing of T cells initiated the development of therapeutic strategies targeting adhesion receptors for organ-specific inhibition of chronic inflammation. As most adhesion receptors have additional immune functions besides mediating leukocyte trafficking, these drugs may have additional immunomodulatory effects. Therapeutic targeting of T-cell trafficking to the central nervous system is the underlying concept of a novel treatment of relapsing remitting multiple sclerosis with the humanized anti-alpha-4-integrin antibody natalizumab. In this chapter, we describe a possible preclinical in vivo approach to directly visualize the therapeutic efficacy of a given drug in inhibiting T-cell homing to a certain organ at the example of the potential of natalizumab to inhibit the trafficking of human T cells to the inflamed central nervous system in an animal model of multiple sclerosis.

Musical Training Induces Functional Plasticity in Human Hippocampus

Training can change the functional and structural organization of the brain, and animal models demonstrate that the hippocampus formation is particularly susceptible to training-related neuroplasticity. In humans, however, direct evidence for functional plasticity of the adult hippocampus induced by training is still missing. Here, we used musicians' brains as a model to test for plastic capabilities of the adult human hippocampus. By using functional magnetic resonance imaging optimized for the investigation of auditory processing, we examined brain responses induced by temporal novelty in otherwise isochronous sound patterns in musicians and musical laypersons, since the hippocampus has been suggested previously to be crucially involved in various forms of novelty detection. In the first cross-sectional experiment, we identified enhanced neural responses to temporal novelty in the anterior left hippocampus of professional musicians, pointing to expertise-related differences in hippocampal processing. In the second experiment, we evaluated neural responses to acoustic temporal novelty in a longitudinal approach to disentangle training-related changes from predispositional factors. For this purpose, we examined an independent sample of music academy students before and after two semesters of intensive aural skills training. After this training period, hippocampal responses to temporal novelty in sounds were enhanced in musical students, and statistical interaction analysis of brain activity changes over time suggests training rather than predisposition effects. Thus, our results provide direct evidence for functional changes of the adult hippocampus in humans related to musical training.

Evaluation of 177Lu-DOTA-sst2 antagonist versus 177Lu-DOTA-sst2 agonist binding in human cancers in vitro

Somatostatin receptor targeting of neuroendocrine tumors using radiolabeled somatostatin agonists is today an established method to image and treat cancer patients. However, in a study using an animal tumor model, somatostatin receptor antagonists were shown to label sst(2)- and sst(3)-expressing tumors in vivo better than agonists, with comparable affinity even though they are not internalized into the tumor cell. In the present study, we evaluated the in vitro binding of the antagonist (177)Lu-DOTA-pNO(2)-Phe-c (DCys-Tyr-DTrp-Lys-Thr-Cys) DTyrNH(2) ((177)Lu-DOTA-BASS) or the (177)Lu-DOTATATE agonist to sst(2)-expressing human tumor samples.

Cloning of farm animals: impact on animal health and welfare and implications in trade

The commercial use of animal cloning for breeding food producing animals has been limited so far by biological and technical constraints such as adverse effects on the health and welfare of animals, especially high perinatal and postnatal disease and mortality of clones. However, the improvement of the technique may overcome those problems in future and contribute to the spread of cloning in agricultural production, which raises concern not only on health and welfare aspects but also on food safety and ethics. This may cause conflict in international trade. The present article reviews these topics on the basis of up-to-date scientific opinions.

Comparative human-horse sequence analysis of the CYP3A subfamily gene cluster

Cytochrome P450 enzymes (CYP450s) represent a superfamily of haem-thiolate proteins. CYP450s are most abundant in the liver, a major site of drug metabolism, and play key roles in the metabolism of a variety of substrates, including drugs and environmental contaminants. Interaction of two or more different drugs with the same enzyme can account for adverse effects and failure of therapy. Human CYP3A4 metabolizes about 50% of all known drugs, but little is known about the orthologous CYP450s in horses. We report here the genomic organization of the equine CYP3A gene cluster as well as a comparative analysis with the human CYP3A gene cluster. The equine CYP450 genes of the 3A family are located on ECA 13 between 6.97-7.53 Mb, in a region syntenic to HSA 7 99.05-99.35 Mb. Seven potential, closely linked equine CYP3A genes were found, in contrast to only four genes in the human genome. RNA was isolated from an equine liver sample, and the approximately 1.5-kb coding sequence of six CYP3A genes could be amplified by RT-PCR. Sequencing of the RT-PCR products revealed numerous hitherto unknown single nucleotide polymorphisms (SNPs) in these six CYP3A genes, and one 6-bp deletion compared to the reference sequence (EquCab2.0). The presence of the variants was confirmed in a sample of genomic DNA from the same horse. In conclusion, orthologous genes for the CYP3A family exist in horses, but their number differs from those of the human CYP3A gene family. CYP450 genes of the same family show high homology within and between mammalian species, but can be highly polymorphic.

Cell-specific expression of human HGF by alveolar type II cells induces remodeling of septal wall tissue in the lung: a morphometric study

Hepatocyte growth factor (HGF) is involved in development and regeneration of the lungs. Human HGF, which was expressed specifically by alveolar epithelial type II cells after gene transfer, attenuated the bleomycin-induced pulmonary fibrosis in an animal model. As there are also regions that appear morphologically unaffected in fibrosis, the effects of this gene transfer to normal lungs is of interest. In vitro studies showed that HGF inhibits the formation of the basal lamina by cultured alveolar epithelial cells. Thus we hypothesized that, in the healthy lung, cell-specific expression of HGF induces a remodeling within septal walls. Electroporation of a plasmid of human HGF gene controlled by the surfactant protein C promoter was applied for targeted gene transfer. Using design-based stereology at light and electron microscopic level, structural alterations were analyzed and compared with a control group. HGF gene transfer increased the volume of distal air spaces, as well as the surface area of the alveolar epithelium. The volume of septal walls, as well as the number of alveoli, was unchanged. Volumes per lung of collagen and elastic fibers were unaltered, but a marked reduction of the volume of residual extracellular matrix (all components other than collagen and elastic fibers) and interstitial cells was found. A correlation between the volumes of residual extracellular matrix and distal air spaces, as well as total surface area of alveolar epithelium, could be established. Cell-specific expression of HGF leads to a remodeling of the connective tissue within the septal walls in the healthy lung, which is associated with more pronounced stretching of distal air spaces at a given hydrostatic pressure during instillation fixation.